JP2011039119A - Display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a display device, performing efficient heat radiation while suppressing the cost. <P>SOLUTION: This display device 1000 provided with a display panel 100 includes a light emitting pixel part 111 formed on a partial area of a first face 121 which is the surface of a substrate 120 and including a plurality of light emitting pixels. The display device 1000 includes a thermal diffusion sheet 210 stuck to a part including a high temperature part, which corresponds to an area where the light emitting pixel part 111 is not formed in the first face 121 in a second face 122 which is the back of the substrate 120, and which reaches a higher temperature than the light emitting pixel part 111 when the display panel 100 is driven. The thermal diffusion sheet 210 is a sheet which radiates heat of the part to which the thermal diffusion sheet 210 is stuck. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a display device that displays an image using an organic EL (Electro Luminescence) element.

  In recent years, display devices using organic EL (Electro Luminescence) elements (hereinafter referred to as organic EL display devices) have attracted attention. In the organic EL element, the deterioration of the organic EL element progresses faster as the temperature of the organic EL element becomes higher. That is, the lifetime of the organic EL element becomes shorter as the temperature of the organic EL element becomes higher.

Therefore, various techniques relating to heat dissipation in the organic EL display device are disclosed.
For example, Patent Document 1 discloses a technique for dissipating heat from an organic EL element by sandwiching a layer in which the organic EL element is formed between two layers having thermal conductivity.

  Patent Document 2 discloses a technique for dissipating heat by devising the arrangement of heat dissipating patterns for dissipating heat.

JP 2003-109773 A JP-A-2005-217031

  In an organic EL display device, as a configuration for efficiently radiating heat, it can be considered that a heat diffusion sheet having a heat radiating function is attached to the entire back surface of the display panel. However, with this configuration, there is a problem that the cost of the thermal diffusion sheet increases and the cost of the organic EL display device increases.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a display device that enables efficient heat dissipation while suppressing cost.

  In order to solve the above-described problems, a display device according to an aspect of the present invention includes a display panel that displays an image using an organic EL (Electro Luminescence) element. The display panel includes a substrate, and a light emitting pixel portion formed on a partial region of the first surface, which is the surface of the substrate, and including a plurality of light emitting pixels arranged in a matrix. Each of the plurality of light emitting pixels includes a plurality of organic EL elements, and in the display device, the light emitting pixel portion is formed on the first surface of the second surface which is the back surface of the substrate. A first heat diffusion sheet attached to a portion corresponding to a non-existing region and including a high-temperature portion that is a portion having a temperature higher than that of the light-emitting pixel portion when the display panel is driven, The 1 heat diffusion sheet is a sheet that radiates the heat of the portion where the first heat diffusion sheet is attached.

  That is, a display device including a display panel includes a light-emitting pixel portion that is formed on a partial region of the first surface that is the surface of the substrate and includes a plurality of light-emitting pixels. Further, the display device is a portion corresponding to a region where the light emitting pixel portion is not formed on the first surface of the second surface which is the back surface of the substrate, and the light emitting pixels are driven when the display panel is driven. The 1st heat diffusion sheet affixed on the part containing the high temperature part which is a part used as a temperature higher than a part is provided. The first heat diffusion sheet is a sheet that dissipates the heat of the portion where the first heat diffusion sheet is attached.

  Therefore, the heat of the high temperature part can be efficiently radiated by the first heat diffusion sheet. The first heat diffusion sheet is attached to a portion of the second surface corresponding to a region where the light emitting pixel portion is not formed on the first surface and including a high temperature portion. That is, the first heat diffusion sheet is attached to a part of the second surface, not the entire second surface. Therefore, the cost of the first heat diffusion sheet can be reduced.

That is, efficient heat dissipation can be performed while reducing costs.
Further, when the horizontal distance between the first heat diffusion sheet and the light emitting pixel closest to the first heat diffusion sheet among the plurality of light emitting pixels is a and the thickness of the substrate is b, a> It is preferable to satisfy b.

  Moreover, it is preferable that the said display apparatus is further provided with the thermal radiation part for contacting the said 1st heat diffusion sheet and radiating heat.

  Further, the display device further includes a second heat diffusion sheet attached to at least a part of a portion of the second surface corresponding to a region where the light emitting pixel portion is formed on the first surface. A thermal diffusivity of the first thermal diffusion sheet is greater than a thermal diffusivity of the second thermal diffusion sheet, and a distance between the first thermal diffusion sheet and the second thermal diffusion sheet is c, When the thickness is b, it is preferable that c> b is satisfied.

Thereby, the heat dissipation effect of the heat | fever which a light emitting pixel part emits can be heightened.
The material forming the first heat diffusion sheet is preferably graphite.

  According to the present invention, efficient heat dissipation can be performed while suppressing costs.

It is a top view of the display apparatus in a 1st embodiment. It is sectional drawing of the display apparatus in 1st Embodiment. It is a top view of the display apparatus in a 1st embodiment. It is sectional drawing of the display apparatus in the modification of 1st Embodiment. It is a top view of the display apparatus in the modification of 1st Embodiment. It is an external view of a display apparatus.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description, the same parts are denoted by the same reference numerals. Their names and functions are also the same. Therefore, detailed description thereof will not be repeated.

<First Embodiment>
FIG. 1 is a plan view of a display device 1000 according to the first embodiment.

  FIG. 2 is a cross-sectional view of the display device 1000 according to the first embodiment. FIG. 2 shows a cross-sectional view between position A and position A ′ of FIG.

  Referring to FIGS. 1 and 2, display device 1000 includes display panel 100, scan line drive circuit 130, and signal line drive circuits 140.1, 140.2, and 140.3. Hereinafter, each of the signal line driver circuits 140.1, 140.2, and 140.3 is also simply referred to as a signal line driver circuit 140. Note that the number of signal line driver circuits 140 is not limited to three, and may be one, two, four, or more.

  The display panel 100 is an active matrix display panel. The display panel 100 is an organic EL panel using an organic EL (Electro Luminescence) element.

  The display panel 100 includes a light emitting unit 110 and a substrate 120. The substrate 120 is a glass substrate made of glass. The substrate 120 is not limited to glass, and may be a substrate made of other materials.

The substrate 120 has a first surface 121 that is the surface of the substrate 120.
The light emitting unit 110 is formed on a part of the first surface 121 of the substrate 120. That is, the light emitting unit 110 is formed on the substrate 120. The light emitting unit 110 includes a light emitting pixel unit 111. The light emitting pixel unit 111 is a part that displays an image. The light emitting pixel unit 111 includes a plurality of light emitting pixels PX. The plurality of light emitting pixels PX are arranged in a matrix. Each of the plurality of light emitting pixels PX emits light according to a signal supplied from the outside. Each of the plurality of light emitting pixels PX includes a plurality of organic EL elements.

  Each light emitting pixel PX is electrically connected to the scanning line driving circuit 130 by a scanning line (not shown). Each light emitting pixel PX is electrically connected to one of the three signal line driving circuits 140 by a signal line (not shown). The organic EL element included in each light emitting pixel PX emits light when a current flows through the organic EL element under the control of the scanning line driving circuit 130 and each signal line driving circuit 140. That is, each light emitting pixel PX emits light under the control of the scanning line driving circuit 130 and each signal line driving circuit 140. In addition, since the process for making an organic EL element light-emit is a known technique, detailed description is not repeated.

  The scanning line driving circuit 130 and each signal line driving circuit 140 are arranged in a partial region of the first surface 121 of the substrate 120 as shown in FIG. In addition, as illustrated in FIG. 2, the scanning line driving circuit 130 is disposed on a partial region of the first surface 121 of the substrate 120. Although not shown, each signal line driver circuit 140 is also disposed on a partial region of the first surface 121 of the substrate 120.

  The scanning line driving circuit 130 and each signal line driving circuit 140 generate high heat when displaying an image in the light emitting pixel unit 111. Hereinafter, the time when an image is displayed in the light emitting pixel unit 111 is also referred to as driving of the display panel 100.

  That is, the scanning line driving circuit 130 and each signal line driving circuit 140 generate high heat when the display panel 100 is driven. Accordingly, the temperature of the portion of the substrate 120 where the scanning line driving circuit 130 and each signal line driving circuit 140 are arranged is higher than that of the light emitting pixel portion 111 when the display panel 100 is driven.

  FIG. 3 is a plan view of the display device 1000 according to the first embodiment. FIG. 3 is a view showing the back surface of the substrate 120. That is, FIG. 3 is a diagram illustrating the back surface of the display device 1000.

  2 and 3, substrate 120 has a second surface 122 that is the back surface of substrate 120.

  In FIG. 3, a region R <b> 130 is a region where the scanning line driving circuit 130 is disposed on the first surface 121 that is the surface opposite to the second surface 122 including the region R <b> 130.

  The region R140.1 is a region where the signal line driver circuit 140.1 is disposed on the first surface 121 that is the surface opposite to the second surface 122 including the region R140.1. The region R140.2 is a region where the signal line driver circuit 140.2 is disposed on the first surface 121 that is the surface opposite to the second surface 122 including the region R140.2. The region R140.3 is a region where the signal line driver circuit 140.3 is disposed on the first surface 121 that is the surface opposite to the second surface 122 including the region R140.3.

A heat diffusion sheet 210 is attached to the second surface 122.
The thermal diffusion sheet 210 is a sheet that dissipates the heat of the portion where the thermal diffusion sheet 210 is attached. The thermal diffusion sheet 210 is a sheet having a high thermal conductivity. The thermal diffusion sheet 210 is made of graphite. In this case, the thermal diffusivity of the thermal diffusion sheet 210 is, for example, 1600 to 2000 (10 ⁻⁷ m ² / s). The thermal diffusivity indicates an index of the ease of conducting heat per unit time. The higher the value of thermal diffusivity, the higher the rate of transferring heat per unit time.

  The thermal diffusion sheet 210 also has a function of radiating heat. The larger the value of the thermal diffusivity, the faster the heat diffusion sheet 210 dissipates the heat of the portion where the heat diffusion sheet 210 is attached.

  In addition, the thermal diffusion sheet 210 is not limited to graphite, and may be generated from other materials.

  Further, the heat diffusion sheet 210 prevents the heat generated in the portion where the temperature is higher than that of the light emitting pixel unit 111 (hereinafter referred to as a high temperature part) from being transmitted to the light emitting pixel unit 111 when the display panel 100 is driven. It is affixed to a part including the high temperature part, which is a part of the second surface 122. That is, the thermal diffusion sheet 210 is in contact with the high temperature part.

  The high temperature part is, for example, regions R130, R140.1, R140.2, R140.3.

  In this case, as shown in FIG. 3, the thermal diffusion sheet 210 is attached to the outer peripheral portion of the light emitting unit 110 on the second surface 122. In this case, the shape of the thermal diffusion sheet 210 is, for example, a ring shape as shown in FIG.

  That is, the thermal diffusion sheet 210 is a portion of the second surface 122 corresponding to a region where the light emitting pixel portion 111 is not formed on the first surface 121 and emits light when the display panel 100 is driven. Affixed to a portion including a high temperature portion, which is a temperature higher than that of the pixel portion 111.

  The high temperature part is not limited to the regions R130, R140.1, R140.2, and R140.3. The high temperature part may be, for example, a power supply that supplies an operating voltage to each circuit.

  Here, as shown in FIG. 2, the horizontal distance between the thermal diffusion sheet 210 and the left end position of the light emitting pixel unit 111 is defined as a. That is, a horizontal distance between the thermal diffusion sheet 210 and the light emitting pixel PX closest to the thermal diffusion sheet 210 among the plurality of light emitting pixels PX included in the light emitting pixel unit 111 is defined as a. The thickness of the substrate 120 is b. In this case, the thermal diffusion sheet 210 is arranged so that a> b is satisfied.

  In addition, the display device 1000 includes a plurality of heat radiating portions 310 that are in contact with the lower part of the thermal diffusion sheet 210 as shown in FIG. The heat radiating part 310 is formed of a material for radiating heat (for example, a metal material such as aluminum, stainless steel (SUS), or copper). In FIG. 3, a plurality of heat radiation portions 310 are not shown for easy understanding of the drawing.

  For example, as shown in FIG. 1, each heat radiation part 310 is provided at the left end, the right end, the upper end, and the lower end of the substrate 120. In FIG. 1, twelve heat dissipating parts 310 are provided, but the present invention is not limited to this. For example, 13 or more heat radiating portions 310 may be provided.

  With the above configuration, when the display panel 100 of the display device 1000 is driven, for example, heat generated in the scanning line driving circuit 130 is transmitted to the substrate 120, the heat diffusion sheet 210, and the heat radiating unit 310 and is radiated to the outside. .

  That is, when the display panel 100 of the display device 1000 is driven, for example, heat generated by the scanning line driving circuit 130 is transmitted to the organic EL elements included in each of the plurality of light emitting pixels PX constituting the light emitting pixel unit 111. Can be prevented.

  That is, when the display panel 100 is driven, for example, heat generated in the above-described regions R130, R140.1, R140.2, and R140.3, which are high-temperature portions, is a plurality of light-emitting pixels that form the light-emitting pixel unit 111. Transmission to the organic EL element included in each PX can be prevented.

  Therefore, when an image is displayed on the display panel 100, that is, when the display panel 100 is driven, it is possible to prevent the heat of the high temperature part from being transmitted to each organic EL element.

  The light emission characteristics of the organic EL element vary depending on the temperature of the organic EL element. Specifically, when the same amount of current is applied to the organic EL element, the luminance of light emission increases as the temperature of the organic EL element increases.

  Therefore, when the temperature of the plurality of organic EL elements included in each of the plurality of light emitting pixels PX constituting the light emitting pixel unit 111 is biased when the display panel 100 is driven, the entire light emitting pixel unit 111 for displaying an image is displayed. Temperature becomes uneven. As a result, uneven brightness occurs in the image displayed by the light emitting pixel unit 111. That is, the image quality of the image displayed by the light emitting pixel unit 111 is lowered.

  Further, in the organic EL element, as the temperature of the organic EL element becomes higher, the deterioration of the organic EL element progresses faster. That is, the lifetime of the organic EL element becomes shorter as the temperature of the organic EL element becomes higher.

  However, according to the display device 1000 having the configuration of the present embodiment, when the display panel 100 is driven, for example, it occurs in the above-described regions R130, R140.1, R140.2, and R140.3, which are high-temperature portions. It is possible to prevent heat from being transmitted to the organic EL elements included in each of the plurality of light emitting pixels PX constituting the light emitting pixel unit 111.

  That is, when the display panel 100 is driven, the temperatures of the plurality of organic EL elements respectively included in the plurality of light emitting pixels PX constituting the light emitting pixel unit 111 can be kept substantially uniform. Therefore, when the display panel 100 is driven, the light emission characteristics of each of the plurality of organic EL elements included in each of the plurality of light emitting pixels PX constituting the light emitting pixel unit 111 can be stabilized.

  As a result, when the display panel 100 is driven, the image quality of the image displayed by the light emitting pixel unit 111 can be prevented from being deteriorated. Furthermore, the lifetime of the organic EL element included in each of the plurality of light emitting pixels PX constituting the light emitting pixel unit 111 can be extended.

  Note that graphite has a higher price per unit area than copper used in general heat diffusion sheets. Therefore, when the thermal diffusion sheet 210 is made of graphite, the thermal diffusion sheet 210 is attached only to the minimum necessary part including the high temperature part, which is a part of the second surface 122. The cost of the diffusion sheet can be reduced.

That is, efficient heat dissipation can be performed while reducing costs.
Further, by adopting a configuration in which the heat of the high temperature portion is not transmitted to the light emitting pixel portion 111, the temperature increase of the entire display panel 100 can be suppressed.

<Modification of the first embodiment>
Next, the case where two types of thermal diffusion sheets of different materials are used will be described.

A plan view of display device 1000A in the present embodiment is the same as FIG.
FIG. 4 is a cross-sectional view of a display device 1000A according to a modification of the first embodiment. 4 shows a cross-sectional view between position A and position A ′ in FIG.

  Referring to FIG. 4, display device 1000 </ b> A is different from display device 1000 in FIG. 2 in that heat diffusion sheet 220 is attached to a part of second surface 122 of substrate 120. Other than that, the detailed description will not be repeated because it is the same as display device 1000.

  Here, as shown in FIG. 4, the distance between the thermal diffusion sheet 210 and the thermal diffusion sheet 220 is c. The thickness of the substrate 120 is b. In this case, the thermal diffusion sheet 210 and the thermal diffusion sheet 220 are arranged so that c> b is satisfied. In FIG. 4, c appears to be smaller than b, but actually, the thermal diffusion sheet 220 is attached at a position where c> b is satisfied.

  FIG. 5 is a plan view of a display device 1000A according to a modification of the first embodiment. FIG. 5 is a view showing the back surface of the substrate 120. That is, FIG. 5 is a diagram illustrating the back surface of the display device 1000A. Note that FIG. 5 does not show the plurality of heat radiation portions 310 for easy understanding of the drawing.

  Referring to FIG. 5, a region where heat diffusion sheet 220 is disposed (hereinafter referred to as a heat diffusion sheet region) is a first surface that is a surface opposite to second surface 122 including the heat diffusion sheet region. Reference numeral 121 denotes an area where the light emitting unit 110 is disposed. The light emitting unit 110 includes a light emitting pixel unit 111.

  That is, the thermal diffusion sheet 220 is attached to at least a part of the second surface 122 corresponding to the region where the light emitting pixel unit 111 is formed on the first surface 121.

The thermal diffusion sheet 220 is made of copper. In this case, the thermal diffusivity of the thermal diffusion sheet 220 is approximately 800 (10 ⁻⁷ m ² / s), for example. That is, the thermal diffusivity (1600 to 2000) of the thermal diffusion sheet 210 generated from graphite is larger than the thermal diffusivity (800) of the thermal diffusion sheet 220.

  The price per unit area of the heat diffusion sheet 220 made of copper is lower than the price per unit area of the heat diffusion sheet 210 made of graphite.

The thermal diffusion sheet 220 also has a function of radiating heat.
In addition, the thermal diffusion sheet 220 is not limited to copper, and may be generated from other materials.

  With the above configuration, the thermal diffusion sheet 220 efficiently dissipates heat generated by the light emitting unit 110 when the display panel 100 is driven.

  Therefore, when the display panel 100 is driven, the temperature of the organic EL element included in each of the plurality of light emitting pixels PX constituting the light emitting pixel unit 111 included in the light emitting unit 110 can be lowered. Therefore, according to the modification of the present embodiment, the lifetime of the organic EL element can be extended as compared with the first embodiment.

  That is, according to the modification of the present embodiment, the lifetime of the organic EL element can be further extended in addition to the effects obtained by the first embodiment.

  Note that according to the modification of the present embodiment, the effects obtained by the first embodiment can also be obtained. That is, when the display panel 100 is driven, the temperatures of the plurality of organic EL elements respectively included in the plurality of light emitting pixels PX constituting the light emitting pixel unit 111 can be kept substantially uniform. Therefore, when the display panel 100 is driven, the light emission characteristics of each of the plurality of organic EL elements included in each of the plurality of light emitting pixels PX constituting the light emitting pixel unit 111 can be stabilized.

  As a result, when the display panel 100 is driven, the image quality of the image displayed by the light emitting pixel unit 111 can be prevented from being deteriorated.

  In addition, a thermal diffusion sheet 210 having a high thermal diffusivity is attached only to a portion where the temperature is particularly high when the display panel 100 is driven, and a thermal diffusion sheet 220 having a low price per unit area is attached to the other portions. wear.

That is, efficient heat dissipation can be performed while reducing costs.
In addition, the external view of the display apparatus 1000A of the first embodiment and the display apparatus 1000A in the modification of the first embodiment is a view shown in FIG.

  As described above, the display device according to the present invention has been described based on the embodiments, but the present invention is not limited to these embodiments. Unless it deviates from the meaning of this invention, the form which carried out various deformation | transformation which those skilled in the art can think to this embodiment, or the structure constructed | assembled combining the component in different embodiment is also contained in the scope of the present invention. .

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  The present invention can be used as a display device that enables efficient heat dissipation while suppressing cost.

DESCRIPTION OF SYMBOLS 100 Display panel 110 Light emission part 111 Light emission pixel part 120 Substrate 130 Scan line drive circuit 140.1, 140.2, 140.3 Signal line drive circuit 1000, 1000A Display apparatus

Claims (5)

A display device including a display panel that displays an image using an organic EL (Electro Luminescence) element,
The display panel is
A substrate,
A light emitting pixel portion formed on a part of the first surface, which is the surface of the substrate, and composed of a plurality of light emitting pixels arranged in a matrix;
Each of the plurality of light emitting pixels includes a plurality of organic EL elements,
The display device further includes:
Of the second surface, which is the back surface of the substrate, the portion corresponding to a region where the light emitting pixel portion is not formed on the first surface, and the light emitting pixel portion when the display panel is driven A first thermal diffusion sheet attached to a portion including a high-temperature portion that is a higher temperature portion;
The first heat diffusion sheet is a sheet that dissipates heat of a portion to which the first heat diffusion sheet is attached.
Display device. When the horizontal distance between the first heat diffusion sheet and the light emitting pixel closest to the first heat diffusion sheet among the plurality of light emitting pixels is a and the thickness of the substrate is b, a> b Fulfill,
The display device according to claim 1. The display device further includes:
In contact with the first heat diffusion sheet, provided with a heat radiating portion for radiating heat,
The display device according to claim 1. The display device further includes:
A second thermal diffusion sheet that is attached to at least a part of a portion of the second surface corresponding to a region where the light emitting pixel portion is formed on the first surface;
The thermal diffusivity of the first thermal diffusion sheet is greater than the thermal diffusivity of the second thermal diffusion sheet,
When the distance between the first heat diffusion sheet and the second heat diffusion sheet is c and the thickness of the substrate is b, c> b is satisfied.
The display device according to claim 1. The material forming the first heat diffusion sheet is graphite.
The display apparatus in any one of Claims 1-4.

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